int countdigit (int number,int digit){
int d,n,count=0;
n=number;
while (n!=0){
d=n%10;
n=n/10;
if (d==digit) count ++;}
return count;
}
#include<stdio.h>
int main(void)
{
int x,t;
printf("Input an integer: ");
x=123;
t=countdigit(x,2);
printf("Number of digit 2: %d",t);
}